The present invention relates to a new and improved construction of combing machine comprising a detaching roll or roller and an oscillating nipper unit consisting of a bottom or lower nipper and a top or upper nipper, wherein the predetermined spacing for the oscillating nipper unit relative to the detaching roll is adjustable. This predetermined spacing is the spacing between the front edge of a bottom-nipper plate and the nip location at the detaching roll or roller, when the oscillating nipper unit is in a front end position. The combing machine also comprises a top comb which is secured at the bottom or lower nipper by means of top-comb holders which are pivotably adjustable relative to the bottom or lower nipper about an axis or pivot which is substantially parallel to the detaching roll or roller.
By adjusting the predetermined spacing, i.e. the front end position of the oscillating nipper unit, such front end position being the end position adjacent to the detaching roll or roller, the degree of combing-out can be altered and an adaptation to the staple of the fibers to be combed can be achieved. However, since the top-comb pins in the front end position of the oscillating nipper unit always have to be at a very small predetermined distance from the detaching roll or roller, a resetting of the top-comb holders relative to the bottom nipper is required subsequent to an adjustment of the predetermined spacing, in order to restore the aforesaid very small predetermined distance.
If the predetermined spacing is adjusted and the top-comb holders are reset in the aforesaid manner in a known combing machine of the type as described, the result would be a change in the depth of penetration of the top-comb pins into the lap, such lap moving from the bottom-nipper plate to the detaching roll or roller. Consequently, it would be also necessary to elevationally adjust the top-comb pins relative to their carrier plate which is retained in the top-comb holders, in order to obtain fairly constant or uniform penetration conditions and thus avoid the danger or risk of collision of the top-comb pins with the circular comb of the combing machine in the rear end position of the oscillating nipper unit, such rear end position being the end position remote from the detaching roll or roller. However, elevational adjustment of the top-comb pins represents a relatively complicated and time-consuming operation. Furthermore, elevational adjustment will not afford entirely uniform penetration conditions, because the adjustment of the predetermined spacing and the corresponding resetting of the top-comb holders in the known or prior-art combing machine will alter not only the depth of penetration of the top-comb pins, but also the angle of penetration, such angle of penetration being the angle between the top-comb pins and the lap running from the bottom-nipper plate to the detaching roll or roller.